Conventional radio frequency (RF) power amplifiers using a fixed or constant supply voltage are much less efficient when backed off from maximum power. However, complex modulation schemes of the type used in many contemporary wireless communication systems require linear power amplification, which compromises overall system efficiency. Envelope tracking (ET) is an approach to RF power amplifier (PA) design in which the power supply voltage applied to the power amplifier is constantly adjusted to ensure that the amplifier is operating at peak efficiency for the given instantaneous output power requirements. However, all-digital and all-analog envelope tracking each implicate inherent drawbacks.
There is, therefore, a need in the art for improved envelope tracking power amplification.